Warp beaming



WARP BEAMING Filed June 13 Inventor fkfln/c/s JAMES @5168 was 8 7% 541,1 Jury/w & 9 1m Attorneys United States Patent ()fice 3,440,700 Patented Apr. 29, 1969 3,440,700 WARP BEAMING Francis James Berridge, Coventry, England, assignor to Courtaulds Limited, London, England, a British company Filed June 13, 1967, Ser. No. 645,779 Claims priority, application Great Britain, July 12, 1966, 31,240/ 66 Int. Cl. D02h 13/12, 13/28, 13/06 US. Cl. 28-36 22 Claims ABSTRACT OF THE DISCLOSURE A warp beaming apparatus in which the position of a member, for example a comb, is automatically controlled as the diameter of the warp beam increases during winding, by producing an electrical quantity which is proportional to the rotational speed of the beam and an electrical quantity which is variable according to the position of the member so as to tend to maintain a predetermined relationship between the electrical quantities.

This invention relates to beaming, by which term is meant the operation of making a warp beam by winding a number of parallel yarns in sheet form onto a beam.

The normal method of forming a warp beam is to draw the required number of yarns oil a creel from or through yarn guides onto a beam rotating about a horizontal axis. It is important that the yarns should have the same tension throughout the finished warp beam and for this reason it is the normal practice to pass the yarns in sheet form around or through a tensioning device before the yarns are wound onto the beam. Between the tensioning device and the beam there is normally a comb for maintaining the correct spacing between the yarns.

During the production of a warp beam it is also the normal practice to decrease its speed of rotation during winding so as to compensate for its increasing diameter, which would otherwise cause the yarns speed to increase and hence cause the tension in the yarns to vary from a minimum value at the centre to a maximum value at the outside of the warp beam.

As the diameter of a warp beam increases during winding it is necessary to adjust the position of the comb through which the yarns pass, so as to ensure that the yarns do not rise out of the comb. In addition to maintaining the yarns at the correct separation, the base of the comb may be used as a levelling guide for the yarn sheet, so increasing the importance of maintaining the comb at the correct height.

Hitherto, the position of the comb has been controlled by the position of a pressure roller bearing against the beam during winding and mechanically connected to the comb. As the position of the pressure roller changes with increasing warp beam diameter, the height of the comb is correspondingly increased.

An alternative proposal has been to contact the yarn sheet with a spring-loaded rod connected to a microswitch. As the yarn sheet rises during winding the rod lifts and the micro-switch makes contact, whereupon a motor is energised to lift the comb on which the rod is mounted until the micro-switch breaks contact. Both of these proposals involve contact with the yarn sheet which, particularly in the case of light-duty beaming apparatus, can cause yarn breakage or damage.

It has been proposed to adjust the position of a comb without any extra contact between mechanical parts of the beaming apparatus and the yarn sheet by an arrangement employing photocells but the accuracy and reliability of such arrangements are unsatisfactory because of the presence of fly and dust.

In addition to altering the position of a comb during winding a warp beam it is commonly desirable to increase the braking force which can be used when the beam needs to be stopped, for example if a yarn breaks. This is because the inertia of a warp beam increases as its diameter increases and it is normally required to be able to stop a beam rotating by applying the brake within the time taken to wind a given length of yarn onto the beam. This is to ensure that in the event of yarn breakage, the broken end will not become wound onto the warp beam before the beam stops which makes finding the broken end diflicult. Increasing the braking force may be accomplished by adjusting the position of a member of the braking mechanism, usually in connection with a mechanism for adjusting the position of the comb, during winding.

The positions of other members of a beaming apparatus may also be controlled as the diameter of a warp beam increases during winding. For example when a diabolo beam, that is a beam in which the confronting surfaces of the end flanges slope outwardly, is wound, it is necessary to increase the width of the comb as the diameter of the beam increases. In one method of accomplishing this the comb is hinged in the middle and the ends of the comb are moved during winding so as to tend to straighten the comb. Diabolo beams are employed in connection with some types of warp knitting machines.

According to this invention a method of controlling the position of a member of a warp beaming apparatus the position of which is adjusted as the diameter of the warp beam increases during winding a sheet of yarns onto the beam, comprises producing by a first device a first electrical quantity which is proportional to the rotational speed of the beam, producing by a second device a second electrical quantity which changes according to the position of the member, comparing the first and second electrical quantities and producing by a comparator a third electrical quantity according to the comparison effected and moving the member according to the third electrical quantity so as to tend to maintain a predetermined relationship between the first and second quantities. The invention includes a warp beaming apparatus for accomplishing the method of the invention.

Examples ofmembers of the beaming apparatus the position of which may be so controlled are a comb, a tensioning device, a guide, a levelling roller, a break detector and a part of a braking mer hanism.

Usually the winding speed of the beam is maintained throughout winding at a constant value so as to maintain the yarn tension uniform throughout the warp beam. If this is not always the case, or if different winding speeds are to be used for producing warp beams of different yarns, it is preferable that the second electrical quantity produced should also be proportional to the winding speed of the beam. Any increase in winding speed will, of course, be reflected by a similar increase in the rotational speed of the beam, so that the effect of making the second electrical quantity proportional to the winding speed of the beam is to remove from consideration by the comparator any variation in the winding speed. Thus, as, for any constant yarn speed, the rotational speed of the beam is inversely proportional to its diameter, the first electrical quantity is effectively related likewise to the diameter of the beam. The relationship between the first and second electrical quantities may then be used directly to control the movement of the member of the beaming apparatus so as to keep it correctly positioned during winding.

The comparator is preferably adapted so as to produce a third electrical quantity when the first and second electrical quantities are unequal. The means for moving the member then operates so as to tend to equalise the first and second electrical quantities. In this case the second electrical quantity is set to be equal to the value of the first electrical quantity at the commencement of winding, that is with the member positioned correctly when the beam has its smallest effective diameter, and the rotational speed of the beam is the greatest. The value of the second electrical quantity at the termination of winding, when the member is correctly positioned in relation to the beam which is at its maximum diameter, should also be equal then to the value of the first electrical quantity at that time, when the beam is rotating at its lowest speed, if the winding speed is constant. The apparatus will then operate throughout winding to maintain the required relationship between the position of the member and the diameter of the warp beam.

The preferred method of keeping the yarn speed constant during winding is to drive the beam by a constant speed electricmotor through a variable speed device, for example an induction coupling. The effective gear-ratio of the variable speed device is then progressively changed throughout winding as the diameter of the beam increases, for example, by a control circuit responsive to an electric signal having a quantity proportional to the yarns speed. The quantity is preferably a voltage which can be produced conveniently by a third device connected to a roller which is rotatable by contact with the yarn sheet, such as a tensioning roller. In one embodiment of the invention the signal so produced is applied to the second device in such a manner as to make the second electrical quantity proportional to the winding speed.

The first and second electrical quantities may be voltages, currents or frequencies. Preferably however, the first and second electrical quantities are voltages as the equipment for generating signals having variable voltages and the equipment controlled by such signals is both simpler to construct and maintain and cheaper to buy than equipment generating or controlled by signals having variable currents or frequencies.

When the first electrical quantity is a voltage, the first device is preferably a tacho-generator connected to the beam; a tacho-generator being a device for producing a signal the voltage of which is proportional to the rotational speed of its rotor. Similarly, the third device is conveniently a tacho-generator, in which case the quantity of its signal is also a voltage.

Where the first and second electrical quantities are voltages, the second device can conveniently be a rheostat having a resistor and a contact, one of which elements is movable. Preferably the signal from the third device is supplied to one end of the resistor whilst the other end of the resistor is held at a constant voltage, for example at earth potential. If the contact is connected to the member which is movable during winding, the potential on the contact will then be both proportional to the voltage from the third device and variable according to the position of the member. Comparison of the voltage on the contact with the first voltage can then be accomplished by a comparator circuit and the third electrical quantity is produced, when necessary, to adjust the position of the contact so as to tend to keep the first voltage and the voltage on the contact equal, and thereby control the position of the member on which the contact is mounted.

An embodiment of the invention is illustrated, by way of example, by the accompanying drawing in which:

FIGURE 1 is a diagrammatic plan of a beaming apparatus including control circuitry for controlling the beam speed and the height of a comb, and

FIGURE 2 is a diagrammatic elevation of parts of the beaming apparatus shown in FIGURE 1 (excluding the control circuitry).

In the figures a warp beam 1 is rotated by a motor 2 through an induction coupling device 3. The ratio between the speeds of the input and output shafts of the induction coupling device 3 is controlled by signals along cables 4 from a control unit 5.

The sheet of yarns, the edges of which are indicated by chain-dotted lines 6, which is wound onto the warp beam 1, is tensioned by passing it between three tensioning rollers 7, 7 and 7a. The speed of rotation of the front tensioning roller 7a is measured by a tacho-generator 8 and a voltage proportional to the speed is transmitted along a cable 9 to the control unit 5.

The control unit 5 operates so as to tend to maintain the linear speed of the yarn sheet 6, derived from the speed of rotation of the front tensioning roller 7a, at a constant value according to the original manual setting of the unit, by automatically adjusting the ratio between the input and output speeds of the induction coupling device 3, so as to tend to keep the voltage produced by the tacho-generator 8 at a constant value. As the diameter of the warp beam 1 increases during winding the yarns speed would increase but for the control unit 5 which progressively decreases the rotational speed of the beam as necessary to maintain the yarns speed at its predetermined desired value.

Between the front tensioning roller 7a and the warp beam 1 the yarn sheet 6 passes through a comb 10 attached to a vertical rack 11- which is meshed with a pinion 12 on the shaft of a reversible motor 13 so that the height of the comb can be adjusted by rotation of the motor. The height of the comb 10 is determined by the position of a rheostat contact wiper 14, which is mechanically connected to the comb 10 through a linkage shown as a dotted line 15, in relation to the rheostat resistor coil 16. The wiper 14 is connected electrically by a cable 17 to one input of a comparator control unit 18. The other input of the control unit 18 is connected by a cable 19 to a tacho-generator 20 which produces a voltage proportional to the speed of rotation of the warp beam 1. One end A of the coil 16 is earthed whilst the other end B is connected by a cable 21 to the cable 9 between the tacho-generator 8 and the control unit 5. The control unit 18 controls the rotation of the motor 13 by signals fed to it along cables 22.

The control unit 18 functions to maintain the comb 10 at the correct height in relation to the diameter of the warp beam 1 by comparing the potentials applied to its inputs and producing a signal at its output when the potentials at its inputs are unequal. The polarity of the signal produced at the output is such as to produce rotation of the motor 13 in the direction which causes the wiper 14 to move along the coil 16 so as to tend to equalise the potentials at the inputs of the control unit.

At the start of winding, the tacho-generators 8 and 20 are arranged to produce output signals of equal volttages. Thus, the motor 13 will be caused to rotate by the control unit 18 until the wiper 14 is at the end B of the coil 16.

As winding progresses, the diameter of the warp beam 1 increases and its rotational speed is decreased in inverse relationship so as to keep the yarns speed constant. Thus the voltage supplied by the tacho-generator 20 to the control unit 18 decreases during winding. The control unit 18 then produces a signal so as to cause rotation of the motor 13 until the wiper 14 is moved to the position where the voltages at the inputs of the control unit are made equal.

This process is continued until the warp beam 1 is fully wound and the wiper 14 approaches the end A of the coil 16, and winding is then stopped. After the complete warp beam has been removed the comb 10 is lowered to receive the yarn sheet to be wound onto the next beam. It is unnecessary to set the combs height exactly before commencing winding of the next warp beam as the control unit 18 is able to adjust the position of the comb in either direction of its movement immediately the winding starts. The size of the pinion 12 is, of course, such that the movement imparted to, the comb by rotation of the motor 13 is the same'as' the radial growth of the warp beam during winding.

The use of different winding speeds for forming warp beams of;,ditferent yarns does not affect the operation of the control unit 18 because any increase in speed will increase the voltages of the signals derived from both the 'tacho-generators 8 and 20 in the same proportion.

To prevent the beaming apparatus from being rotated when no gyarns are being wound onto the beam, which would cause the variable speed device 3 to run-away in attempting to produce the correct yarns speed at the roller 7a, and cause the control unit 18 to try and raise the comb beyond its maximum possible height, the control unit 5 preferably incorporates a safety switch td 'shut down the apparatus if no signal is received from the tacho-generator 8.

To increase the braking force which may be used to stop the rotation of the warp beam in the event of yarn breakage, and on the termination of winding, a member of the braking mechanism (not shown) can be connected mechanically to the rack 11.

If it is desired to increase the width of a comb during winding a diabolo beam, the comb can be hinged at its centre and the ends provided with pins which are movable in a fixed channel. A rotatable cam is then arranged to bear against the centre of the comb so that as the cam is rotated during winding the comb is straightened. To accomplish this using the apparatus shown inathe drawing the cam is rotated by the motor 13 so that',,the comb is straightened at the same time as it is raised by the rack 11 and pinion 12.

Although in the specific embodiment of the inven tion a motor is used to control the position of the comb, it will be appreciated that other means, for example a hydraulic or pneumatic system, could be used for that purpose. In that case a third electrical quantity would be used to control such other means instead of a motor. The third electrical quantity may be a voltage, a current or a frequency depending on the type of motor or other means used to control the position of the member.

What I claim is:

1. A method of controlling the position of a member of a warp beaming apparatus in which the rotational speed of the beam is decreased during winding as the diameter of the beam increases and in which the position of the member is to be adjusted in dependence upon the diameter of the warp beam, comprising producing a first electrical quantity which is proportional to the rotational speed of the beam, producing a second electrical quantity which is dependent upon the position of the member, comparing the first and second electrical quantities and producing a third electrical quantity according to the comparison efiected, and moving the member according to the third electrical quantity so as to tend to maintain a predetermined relationship between the first and second quantities.

2. A method according to claim 1 wherein the second electrical quantity produced is dependent also upon the winding speed.

3. A method according to claim 1 wherein the first and second electrical quantities are voltages.

4. A method according to claim 1 wherein the third electrical quantity is produced when the first and second electrical quantities are unequal, and the member is moved so as to tend to equalise the first and second electrical quantities.

5. A method according to claim 1 comprising the additional steps of producing an electrical quantity proportional to the winding speed and controlling the rotational speed of the beam by means of this quantity to maintain the winding speed at a constant predetermined value throughout winding each warp beam.

6. A method of controlling the position of a warp guide member of a warp beaming apparatus in which the rotational speed of the beam is decreased during winding as the diameter of the beam increases and in which the position of the member is to be adjusted in dependence upon the diameter of the warp beam, comprising producing a first voltage which is proportional to the rotational speed of the beam, producing a second voltage which is dependent upon the position of the saidmember and which is also dependent upon the winding speed of the beam, comparing the first and second voltages and producing an electrical quantity when the voltages are unequal and moving the said member according to the electrical quantity so as to tend to equalize the first and second voltages.

7. A method according to claim 6 comprising the additional steps of producing an electrical quantity proportional to the winding speed and controlling the rotational speed of the beam by means of this quantity to maintain the winding speed at a constant predetermined value throughout winding each warp beam.

8. In a warp beaming apparatus comprising a beam, means for rotating the beam, means for adjusting the rotational speed of the beam to decrease the rotational speed during winding as the diameter of the beam increases, a member the position of which is to be adjusted as the diameter of the warp beam increases during winding a sheet of yarns onto the beam, and means for adjusting the position of the said member, the improvement wherein said means for adjusting the position of the said member comprises a first device for producing a first electrical quantity which is proportional to the rotational speed of the beam, a second device for producing a second electrical quantity which is dependent upon the position of the said member, a comparator for comparing the first and second electrical quantities and for producing a third electrical quantity according to the comparison effected and means for moving the said member according to the third electrical quantity so as to tend to maintain a predetermined relationship between the first and second electrical quantities.

9. A warp beaming apparatus according to claim 8 wherein the second electrical quantity produced by the sec-ond device is dependent also upon the winding speed.

10. A warp beaming apparatus according to claim 8 wherein the first and second devices are devices for producing voltages.

11. A warp beaming apparatus according to claim 10 wherein the second device comprises a rheostat, the movable element of which is connected to the said member.

12. A warp beaming apparatus according to claim 11 comprising a third device for producing a voltage proportional to the winding speed, said voltage being supplied to one end of the resistor of the rheostat.

13. A warp beaming apparatus according to claim 12 comprising a roller which is rotatable by contact with the Warp sheet, said third device being connected thereto.

14. A warp beaming apparatus according to claim 13 wherein the roller is a warp tensioning roller.

15. A warp beaming apparatus according to claim 8 wherein the comparator is adapted to produce the third electrical quantity when the first and second electrical quantities are unequal, and the means for moving the said member operates so as to tend to equalise the first and second electrical quantities.

16. A Warp beaming apparatus according to claim 8 wherein the beams for moving the said member comprises a reversible electric motor.

17. In a warp beaming apparatus comprising a beam, means for rotating the beam, means for adjusting the rotational speed of the beam to decrease the rotational speed during winding as the diameter of the beam increases, a warp guide member the position of which is to be adjusted as the diameter of the warp beam increases during winding a sheet of yarns onto the beam, and means for adjusting the position of the said warp guide member, the improvement wherein said means for adjusting the position of the said member comprises a first device for producing a first voltage which is proportional to the rotational speed of the beam, a second device for producing a second voltage which is dependent upon the winding speed of the beam and is also dependent upon the position of the said member, a comparator for comparing the first and second voltages and for produc ing an electrical quantity when they are unequal and means for moving the said member according to the electrical quantity so as to tend to equalize the first and second voltages.

18. A warp beaming apparatus according to claim 17 comprising a third device for producing a voltage proportional to the winding speed of the warp beam and wherein the second device comprises a rheostat, the movable element of which is connected to the said member, the said voltage produced by the third device being supplied to one end of the resistor of the rheostat.

19. A warp beaming apparatus according to claim 18 comprising a roller which is rotatable by contact with the warp sheet, said third device being connected thereto.

20. A warp beaming apparatus according to claim 19 wherein the roller is a warp tensioning roller.

21. A warp beaming apparatus according to claim 17 wherein the means for moving the said member comprises a reversible electric motor.

22. A warp beaming apparatus according to claim 21 wherein the member is a comb and the means for moving the comb additionally comprises a rack, to which the comb is attached, and a pinion on the motor which is meshed with the rack, the rack and the comb being moved when a third electrical quantity is produced by the comparator.

References Cited UNITED STATES PATENTS 1,663,493 3/1928 Clay.

1,857,817 5/1932 McCann.

3,072,998 1/1963 Bijl 28-32 3,263,297 8/1966 Manning 28--35 LOUIS K. RIMRODT, Primary Examiner.

US. Cl. X.R. 2872.5 

